A flexible nonextensible rope of mass ρ per unit length and length equal to 1/4 of the c...

A flexible nonextensible rope of mass ρ per unit length and length equal to 1/4 of the circumference of the fixed drum of radius r is released from rest in the horizontal dashed position, with end B secured to the top of the drum. When the rope finally comes to rest with end A at C, determine the loss of energy ΔQ of the system. What becomes of the lost energy?